1. Field of the Invention
This application relates to the treatment of air and water with ozone in appliances to effectively disinfect the air and/or water. More particularly, it relates to apparatus and methods to efficiently and effectively treat air and water in appliances such as refrigerators, dishwashers, and washing machines in a cost efficient manner.
2. Prior Art
The disinfection properties of ozone are well documented. There have been suggestions that ozone be used in appliances to assist in suppressing the growth of bacteria and fungus, thus minimizing decay and suppressing the generation of unpleasant odors.
There is a need for an apparatus that can be applied to an appliance economically and effectively to use ozone to suppress bacterial growth in both water and air. Further, the apparatus should be capable of producing water with reduced microbiological content, on demand, without the need to have a large storage tank, in which water may be held for long periods of time and in which bacteria may grow prior to the demand for the water.
It is an object of the present invention to provide an apparatus that conveniently provides disinfected water and a supply of ozone-enriched air, which can be used to suppress subsequent biological activity or can be used to control biological growth within the appliance.
It is a further object of the invention to provide disinfected water to a number of devices which may require it, on demand.
It is another object of the invention to provide air having the ability to suppress biological activity on a periodic basis, to an appliance such as in a refrigerator or washing machine, and possibly to a food storage space in the same general area as the appliance.
The invention is directed to an appliance capable of receiving an oxygen-containing gas and water, the appliance including an apparatus for treating the oxygen containing gas and water. It is also directed to a system for use in such an appliance. The apparatus comprises a source of ultraviolet radiation; a first input associated with the source for receiving water to be exposed to the radiation; a first output for the water that has been exposed to the radiation; a second input associated with the source for receiving the oxygen containing gas to be exposed to the radiation so that ozone is formed in the gas; and a second output for the gas containing the ozone. It should be noted that while ultraviolet light produces ozone, ultraviolet light may also produce other chemicals or reactive species that are also effective as disinfectants. However, we refer to all of these disinfecting species as xe2x80x9cozonexe2x80x9d herein.
Preferably, the oxygen containing gas is air. The source of ultraviolet radiation may be a mercury filled electrical bulb. The appliance may be a refrigerator, a dishwasher, a clothes washing machine, a clothes dryer, and a clothes washer/dryer. The apparatus may be mounted inside or outside the appliance.
The appliance may further comprise a controller for controlling the source of ultraviolet radiation so that the source is turned on when water begins to flow into the first input, and remains on for a fixed period of time after water ceases to flow into the input, so that water which has flowed into the input but has not yet flowed out of the output is fully treated. The controller may periodically cause the source of ultraviolet radiation to be turned on to periodically ensure treatment of the water held in the device.
The appliance may further comprise a storage vessel for storing disinfected (and chilled) water. The storage vessel may be pressurized so that disinfected water can be dispensed on demand.
The appliance may further comprise a pressure or flow sensor for detecting a drop in pressure or start of flow at the first output, and a flow activating apparatus for activating flow of water into the first input when a drop in pressure or start of flow is detected by the pressure or flow sensor.
The appliance may further comprise a sensor for detecting ultraviolet radiation produced by the source; and the flow activating apparatus may activate the flow of water into the first input only when both the drop in pressure or flow of water, and detection of ultraviolet radiation by the sensor simultaneously occur.
The appliance may further comprise a filter apparatus disposed to filter water of certain chemical or particulate contaminants prior to the water entering the first input.
The apparatus may further comprise a housing, the source of ultraviolet radiation being disposed in the housing; a first plenum through which water may be caused to flow from the first input to the first output, the first plenum being sized, shaped, and positioned so that water in the first plenum is exposed to the ultraviolet radiation to a degree sufficient to suppress biological activity in the water; and a second plenum through which air may be caused to flow from the second input to the second output, the second plenum being sized, shaped, and positioned so that when the gas is in the second plenum, the gas is exposed to the ultraviolet radiation to a degree sufficient to form ozone in the gas. The first plenum and the second plenum may be cylindrical and coaxial.
The apparatus may further comprise a tube through which the water flows from the first input to the first output, the tube having characteristics that permit the ultraviolet radiation to suppress biological activity in the water; and a plenum through which gas may be caused to flow from the second input to the second output, the plenum being sized, shaped, and positioned so that when the gas is in the plenum, the gas is exposed to the ultraviolet radiation to a degree sufficient to form ozone in the gas. The tube is substantially transparent to the ultraviolet radiation and may be formed of tetraflouroethylene or quartz.
The appliance may further comprise at least one gas conducting means for conducting the ozone containing gas to a location remote from the appliance, the location being, for example, a storage area for food. The appliance may further comprise a bubbler to produce ozone-enriched water that can be used as a disinfectant, as a bleach, or to control re-growth of bacteria and other microbiota.
The invention is also directed to a method for reducing biological activity in an appliance, which is capable of receiving an oxygen containing gas and water. The method comprises generating ultraviolet radiation; exposing the oxygen containing gas and the water in the appliance to the radiation to suppress biological activity in the water and to generate ozone in the gas. The exposing of the gas and the water may occur simultaneously. Preferably, the gas is air, but it could be other fluids.
In the case of the appliance being a refrigerator, the method further comprises circulating the gas containing the ozone through the food containing compartments of the refrigerator, including circulating the gas periodically, possibly for a short period of time each day, such as when the refrigerator is not generally in use, as for example, during night time hours or during periods of time when the inhabitants are working. For example, the gas may be circulated for a period of time between thirty seconds and two hours once every day.
The source of ultraviolet radiation may be turned on when water is to be disinfected for use. In that case, it is not necessary to circulate the gas.
The method may further comprise conducting the ozone containing gas to a location remote from the appliance, such as to a food storage space. A bubbler may be used to produce ozone-enriched water that can be used as a disinfectant, as a bleach, or to control re-growth of bacteria and other microbiota.